Known mill drive systems comprise one or more transmission stages for drive power conversion of an electric motor. The transmission stages and the electric motor in this case form a drive train, which is coupled tightly to a processing process within, for example, a bowl mill, a pug mill, a crusher, a tube mill or a tubular rotary kiln and is subjected to considerable reactions from the processing process. Generally, bevel gear stages are used for linking the electric motor to the drive train.
DE 39 31 116 A1 has described a drive apparatus for a mill with a vertical design, in which a housing of an auxiliary transmission is screwed fixedly to the mill. In this case, a precise alignment of axes, which are far apart from one another, of the drive pinion and the toothed ring is necessary. Furthermore, introducing axial mill forces via an axial thrust bearing into a common transmission housing results in considerable loads for a meshing engagement in the auxiliary transmission. As a result of a common large transmission and mill bearing interior, rapid contamination with lubricating oil for the drive apparatus is favored. In addition, a mechanical torque division in the auxiliary transmission has proven to be problematic in teems of a lack of compensation for excessive constraining forces.
JP 2005 052799 A has disclosed a drive apparatus for a vertical crusher, which is driven either via a toothed ring on a rotatable base plate or via a multi-stage bevel gear transmission. As a result of a lack of adjustment movability at an output stage of the drive apparatus, impact loads are transferred from the processing process into the drive apparatus, in particular into the toothing thereof.
WO 2009/068484 A1 has described a spur gear transmission with one or more transmission stages for driving a machine tool, enclosed by a toothed ring, which spur gear transmission comprises a transmission housing accommodating the transmission stages and a pinion which is capable of an adjustment movement, is arranged on an output shaft of an output stage and meshes with the toothed ring. The transmission housing comprises a first housing part, which is rigid per se and a second rigid housing part. The first housing part surrounds the output stage with the output shaft and the pinion, which is capable of an adjustment movement, and has side walls which protrude beyond the transmission and rest on the pedestal. The second housing part is fastened on the first housing part on an end side without any touching contact with the pedestal.